1. Field of The Invention
This invention relates to an actuator used, for example, for a door locking system which may lock or unlock a door automatically.
2. Description Of The Prior Art
Heretofore, there has been used an actuator as shown in FIG. 8 (see Japanese Patent Disclosure No. 60-59278/85).
An actuator 100 shown in the figure is fitted with a motor 102 in a motor fitting part 101a provided to a casing 101. The motor 102 is installed in the casing 101 so as to align the logitudinal direction of the motor 102 with the direction of the thickness of the casing 101 by pressing a bar 103 onto an end cover 102 of the motor 102 and driving screw 104 through the bar 103 into the casing 101.
A pinion 105 is force-fitted onto the shaft 102b protruding from the end cover 102a along the longitudinal direction of said motor 102, and is meshed with a larger gear part 106a of an intermediate gear 106 which has the larger gear part 106a and a smaller gear part 106b as one body and is supported rotatably by an intermediate shaft 107.
A sector wheel 109 is fixed to an output shaft 108 supported rotatably by the casing 101, and is so designed as to rotate oscillatively within a range restricted by dampers 101b and 101c provided to the casing 101. The smaller gear part 106b of the intermediate gear 106 is meshed with said sector wheel 109.
Additionally, a swing arm 110 is fixed to the output shaft 108 on the outside of the casing 101 in order to transmit the output to the outside.
Upon supplying a prescribed electric current to the motor 102 through a terminal 102c or 102d, the shaft 102b of the motor 102 rotates in the forward or reverse direction.
By the rotation of the shaft 102b of the motor 102 in forward direction, the power of the shaft 102b is transmitted to the sector wheel 109 from the pinion 105 through the larger gear part 106a and the smaller gear part 106b of the intermediate gear 106, and the sector wheel 109 engages the damper 101b provided to the casing 101. The sector wheel 109 engages another damper 101c when the shaft 102b of the motor 102 rotates in the reverse direction, said sector wheel 109 rotates oscillatively in the range in which the sector wheel 109 is out of contact with either damper 101b or 101c.
Thereby the swing arm 110 functions, a door (not shown) is locked and unlocked by getting a door lock rod 111 up and down which is connected with said swing arm 110.
However, in the conventional actuator 100 as mentioned above, because the motor 102 is fitted into the motor fitting part 101a provided to the casing 101 in a state in which the longitudinal axis of the motor 102 and the thickness of the casing 101 are the same, it is difficult to make the depth of the casing 101 small which is equivalent to the length of the shaft 102b of the motor 102. Therefore, there is a problem in that it is impossible to make the actuator 100 as desired.